1. Field of the Invention
The present invention relates to a Bluetooth-IP access system, especially, to the Bluetooth-IP access system capable of fast accessing an IP based network through the Bluetooth in a Bluetooth terminal and a Bluetooth-IP access device having broadband and large capacity in addition to fast search function.
2. Description of the Prior Art
In a general Bluetooth-IP access system, a terminal comes into an inquiry state to search an access point, and the access point comes into an inquiry scan state to find nearby access points. The inquiry is designated as a process to find the clock and the device access code (DAC) present within the inquiry range.
When the access points receives the ID packet for inquiry in an inquiry scan state, it comes into the previous state of the inquiry scan state, and then stands by for 0 to 64 ms. At this time, if there is not external input, it comes into the inquiry scan state again, and if it receives the ID packet for inquiry, a Bluetooth device of the access point comes into the inquiry scan state and transmits the FHS (Frequency Hopping Synchronization) packet having an information for synchronizing frequency between different Bluetooth devices. After transmitting the FHS packet, the Bluetooth device increases an offset of an inquiry hop sequence by “1” and maintains the inquiry scan state again.
For example, it takes at least 2.56 sec for a Bluetooth terminal to perform search of 8 access points squarely and uniformly distributed. Furthermore, when any one of an access point and a terminal is transmitting data, it takes more time to perform search. The Bluetooth terminal can form ACL (Asynchronous Connection Less) link by paging with information included in the FHS packet obtained from the above-mentioned search result. Meanwhile, when the Bluetooth terminal perform paging, it uses clock_offset CLKE27-2 included in the FHS packet in order to increase access speed.
If the distance for the simultaneous communication between 2 access devices and the terminal is 2 m, the Bluetooth terminal moving at a speed of 1 m/s has to search 8 nearby access points within 2 sec and connect the optimal access point to perform handoff without losing connection.
Therefore, to perform simultaneous communication between the Bluetooth terminal and 2 access devices in a prior art, the speed of the terminal has to be decreased or the distance between the Bluetooth terminal and 2 access devices has to be increased. Furthermore, the paging and inquiry for access point search change the frequency 3200 times per second, leading to the great interference and the power-consumption.